<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<div>
  <input type="text" v-model="n1">
  <input type="text" v-model="n2">
  <input type="button" value="加" @click="f('+')">
  <input type="button" value="减" @click="f('-')">
  <input type="button" value="乘" @click="f('*')">
  <input type="button" value="除" @click="f('/')">
  <h1>{{result}}</h1>
</div>
<script src="https://lf3-cdn-tos.bytecdntp.com/cdn/expire-1-M/vue/2.6.14/vue.js"></script>
<script>
  let v = new Vue({
    el:"div",
    data:{
      n1:"",
      n2:"",
      result:"结果",
    },
    methods:{
      f:function (x) {
        v.result = eval(v.n1+x+v.n2)
      }
    }
  })
</script>
</body>
</html>